The top picture is of a Ford lift cover from either a 9N or 2N; the bottom picture is of a lift cover from a late '53 or '54 TEA20 (20-85), above serial number 350,000. Over the years, certain areas were strengthened and improvements made, and these can be seen on the lift cover in the bottom picture: a) on the lift cylinder where the front bolts go through b) on the lift cover casting where the lift arm shaft passes through, and where the control quadrant mounts c) on the lift cylinder where the spring connects (?) What is not easily seen in the top picture is that on the earliest models, there is no place to tap in to the hydraulic system, as there is on the newer  ones. Interim models had a 3/8" NPT hex-head plug that could be removed (with great difficulty)  to gain access. By the time the lift cover in the bottom photo was made, this had been upped to 1/2" NPT, with much larger, square- headed bolts (just visible in the bottom photo).